Slack to Microsoft Teams: What the Switch Actually Costs
If your company already pays for Microsoft 365, moving from Slack to Teams can look free. It isn't, and the timing of your Slack renewal can matter more than the licence price. Here are the real numbers for a 50-person team.
Quick answer: For a 50-person team on Slack Business+ that already has Teams through Microsoft 365, our worked example breaks even in month 6, or month 12 if you still have six months of Slack to pay. A team on Slack Pro moving to Teams Essentials saves much less per seat: with no contract overlap it breaks even in month 27, and with six months left on Slack it doesn't pay back within three years. The main one-time costs are internal time and the fact that Teams can't import Slack direct messages.
What you pay today
Prices below are US list prices as shown on the vendors' pricing pages in September 2026. Your contract may differ, so use your own numbers in the calculator.
| Plan | Per user / month (annual) | Monthly billing |
|---|---|---|
| Slack Pro | $7.25 | $8.75 |
| Slack Business+ | $15.00 | $18.00 |
| Microsoft Teams Essentials | $4.00 | — |
| Microsoft 365 Business Basic (includes Teams) | $7.00 | — |
| Microsoft 365 Business Standard with Copilot (includes Teams) | $23.50 | — |
Sources: Slack pricing, Microsoft Teams business options, Microsoft 365 business plans. Slack's Business+ price rose to $15 in 2025 as part of Salesforce's pricing update.
The costs a price comparison misses
1. Your Slack contract doesn't end when you leave
Slack lets you choose whether a plan change takes effect immediately or at renewal. When you move down between paid plans, Slack credits the unused time to your workspace, but those credits "have no currency or exchange value," are non-refundable, and expire when your paid plan ends. In practice, if you are on an annual plan, the months left on it are money you have already committed. That is the contract overlap our calculator counts. (Slack's Fair Billing Policy does credit you for members inactive for 28 days, but again as credits, not cash.)
2. Your message history may not all come with you
On Slack's Free and Pro plans, workspace owners can export public channels only. Exporting private channels and direct messages requires an application and approval, and the broader "all conversations" export is a Business+ and Enterprise feature. On the Teams side, Microsoft's own migration guide says there is no native Slack import tool, recommends free GitHub tools or partner solutions for channel history, and states that "Teams doesn't support importing Direct messages currently." Files in a Slack export usually arrive as links that need a script to download.
Decide early what history you actually need. Many teams keep a read-only archive of the Slack export and move only active channels and files.
3. Integrations and workflows need rebuilding
Microsoft suggests finding equivalent apps in the Teams store and pointing webhooks at Microsoft 365 connectors. Every bot, workflow and alert your team relies on is a small project. List them before you set a date.
4. People's time
Microsoft's guide describes three phases: assess your Slack workspaces and map users to Microsoft accounts; design your teams and channels; then create them, copy files, set up apps and switch people over, ideally removing Slack access on the day each person is added to Teams. For the example below we assume 90 hours in total for a 50-person team: about 40 hours of admin and planning, plus an hour of training and adjustment per person. That is our assumption, not a vendor figure. Replace it with your own.
Worked example: 50 people
All scenarios use the switching cost calculator with 50 seats, 90 hours of internal time at $50 an hour ($4,500 one-time), no paid migration tool, and a 5% annual price rise on both sides.
| Scenario | Slack months left | Break-even | 3-year difference |
|---|---|---|---|
| A. Business+ ($15) → Teams already included in Microsoft 365 | 0 | Month 6 | +$23,873 |
| A. Same, mid-contract | 6 | Month 12 | +$19,373 |
| B. Pro ($7.25) → Teams Essentials ($4) | 0 | Month 27 | +$1,647 |
| B. Same, mid-contract | 6 | Not within 36 months | −$528 |
Scenario A is the common one: a company already licensed for Microsoft 365, paying for Slack on top. Because Teams adds no licence cost, $9,000 a year of Slack spend disappears, and the $4,500 of internal time pays back in six months. Switching halfway through an annual Slack term adds $4,500 of Slack you still pay for and doubles the payback period.
Scenario B is a team with no Microsoft 365 that wants the cheapest option. The saving is $3.25 a seat, so the same $4,500 of internal time takes more than two years to recover, and switching mid-contract means it never pays back within three years. For this team, the cheapest decision may be to stay, or to move only at renewal.
A checklist before you switch
- Find your Slack renewal date and whether you are on annual or monthly billing. Plan the cut-over for renewal.
- Check what you can export on your Slack plan, and apply for private-channel and DM export early if you need it.
- Decide what history moves: active channels and files, or everything. Keep a read-only archive of the rest.
- List every integration, bot and workflow, with an owner for each replacement.
- Map users from Slack emails to Microsoft accounts before you create teams.
- Check your licences: if some users don't have Teams today, price the plan they would need.
- Run the numbers in the calculator with your own hours and contract dates.
Related: Zoom to Google Meet (worked example), Jira to Linear (another worked example), the hidden costs of switching SaaS tools, how to negotiate a renewal (useful if you decide to stay), and how long migrations take.
Open the switching cost calculator
This is a worked example, not procurement advice. List prices change and many organizations pay negotiated rates; check your own contract. We have no commercial relationship with Slack, Salesforce or Microsoft.